1. Field of the Invention
This invention relates to an apparatus and method which recognize information stored in a radio frequency identification (RFID) tag by use of radio communication and an article sales data processing apparatus which processes article sales data based on information stored in the RFID tag.
2. Description of the Related Art
In recent years, as a non-contact type article recognition system utilizing electromagnetic waves, a system using RFID tags has been developed. Basically, the system is configured by RFID tags, an RFID tag reader and an information processing apparatus. The RFID tags are respectively attached to articles to be recognized. The RFID tag reader reads storage information items of the RFID tags attached to the respective articles by use of radio waves. The information processing apparatus recognizes an article to which the RFID tag is attached based on information read by the RFID tag reader.
For example, the article recognition system using RFID tags is used for a check out system in a supermarket or the like. One example of the system is disclosed in Jpn. Pat. Appln. KOKAI Publication No. H10-049756.
The RFID tag is attached to each article. In the memory of the RFID tag, article information such as an identification code of an article to which the tag is attached is stored. The RFID tag reader is provided on an article placing portion on which articles to be purchased by customers are placed. Therefore, if articles to be purchased by customers are placed on the article placing portion, article information items of the RFID tags attached to the respective articles are read by the RFID tag reader.
An information processing apparatus is connected to the RFID tag reader. The information processing apparatus recognizes an article to be purchased by a customer according to article information of the RFID tag read by the RFID tag reader. Then, it performs the settlement process for the articles.
Further, this type of article recognition system is utilized for a check out system in a self-service type dining hall. One type of this system is disclosed in Jpn. Pat. Appln. KOKAI Publication No. 2004-102563.
The RFID tag is attached to each, bowl, cup, dish or the like (in this specification, a dish is used as a representative). In the memory of the RFID tags, information items of menu articles to be served in dishes to which the RFID tags are attached are stored. The RFID tag reader is provided on a tray placing portion on which a tray is placed. The user places dishes of menu articles ordered on a tray and then places the tray on the tray placing portion. Thus, the menu article information items of the RFID tags attached to the dishes on the tray are read by the RFID tag reader.
An information processing apparatus is connected to the RFID tag reader. The information processing apparatus recognizes menu articles of food which the user will eat or drink according to the menu article information items of the RFID tags read by the RFID tag reader. Then, it performs the settlement process for the menu articles.
In the above article recognition system, a function of anti-collision is used. The function of anti-collision is a control function of simultaneously reading storage information items of the RFID tags when a plurality of RFID tags are present in the communication area of one antenna of the RFID tag reader.
However, the RFID tag reader cannot always communicate with all of the RFID tags present in a communicable range of the antenna. There occurs a possibility that an RFID tag cannot communicate due to superposition of RFID tags, influence by noise or the like. Further, there occurs a possibility that an RFID tag is damaged.
Conventionally, when an RFID tag which could not communicate with the RFID tag reader was present, the information processing apparatus could not recognize the storage information of the RFID tag. However, the information processing apparatus determined the information sent from the RFID reader. Therefore, the operator of the information processing apparatus was required to determine whether storage information items of the RFID tags attached to all of the to-be-recognized articles could be recognized or not.